In this article, we will see how to parse XML and count instances of a particular node attribute in Python.

What is XML?

Extensible Markup Language (XML) Extensible Markup Language (XML) is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. It is a markup language like HTML, and It is designed to store and transport data. Here, we will use built-in XML modules in python for parsing XML and then counting the instances of a node. We use ElementTree XML API and minidom API to parse our XML file.

XML code for a note is given below:

It should be saved as a country_data.xml file in the same directory.

<?xml version="1.0"?>
<data>
    <country name="France">
        <rank>1</rank>
        <year>2008</year>
        <gdppc>141100</gdppc>
        <neighbor name="Germany" direction="E"/>
        <neighbor name="Spain" direction="N"/>
    </country>
    <country name="Poland">
        <rank>4</rank>
        <year>2011</year>
        <gdppc>59900</gdppc>
        <neighbor name="Germany" direction="W"/>
    </country>
    <country name="Italy">
        <rank>68</rank>
        <year>2015</year>
        <gdppc>13600</gdppc>
        <neighbor name="France" direction="N"/>
    </country>
</data>

Example 1: 

In this example, We will use xml.etree.ElementTree module for parsing our XML file and storing in tree variable and after that we will find all the instances of a particular node attribute with the python findall() function of this module. Now we iterate over a list and check for a particular node attribute value if it matches then we will increment count as 1 to our variable.

# Importing our module 
import xml.etree.ElementTree as ET


# Finding the Node Attribute with name tag 
# neighbor and name value as "Germany"
Name_attribute = "France";

# Parsing our xml file 
tree = ET.parse('country_data.xml')
root = tree.getroot();

# Counting the instance of Node attribute with findall 
NO_node = 0 ;
for instance in root.findall('country/neighbor'):
    # Checking for the particular Node Attribute 
    if instance.get('name') == Name_attribute:
        NO_node+=1;

# Printing Number of nodes
print ("total instance of given node attribute is : ", NO_node)

Output:

total instance of given node attribute is :  1

Example 2:

In this example, we will parse our XML file with the help of minidom module and assign this to the doc variable, getElementsByTagName() function returns a list of instances of a particular node. Now we iterate over a list and check for a particular node attribute value if it matches then we will increment count as 1 to our variable.

# Importing our module 
from xml.dom import minidom


# Finding the node instance with name "Germany"
Name_attribute = "Germany";

# Parsing our xml file 
doc = minidom.parse('country_data.xml')
root = doc.getElementsByTagName('neighbor')

Number_attributes = 0;
for i in root:
    # print ctypes.cast(i, ctypes.py_object).value
    if i.attributes['name'].value == Name_attribute:
        Number_attributes += 1;
        
# Printing Number of nodes
print ("Total instance of Particular node attribute is : " ,Number_attributes)

Output:

Total instance of Particular node attribute is :  2